I just wondered what Plugins are neceassary to create such a liquid looking effect like in this video:
Those paint splats are often done with stock footage or filmed footage. Get a black or green surface, throw some paint at it and film it. Bring it in to AE and extract the alpha from the luma or with chroma-key and then re-colour the paint however you like using your colour correction tools of choice.
To make liquid effects in AE without footage, here's the technique I've been using since forever. I worked it out myself years ago, but so did a lot of other people, so I won't claim to have invented it
Take your source layer, eg. text, footage whatever. Apply the turbulent displace filter to it, starting with 0% strength and ramping up. Muck around with the settings and animate the evolution setting until it looks like you want it. Then apply a blur, again, starting at 0 then ramping up. Then use the extract filter to harden the edges of the blurred outlines. Lastly use the fill filter to fill in the layer with a solid colour. The effect will be something dissolving into blobs of liquid. Works best with line art and text, or high contrast footage.